Book/Dissertation / PhD Thesis

FZJ-2021-02522

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Single-Trap Phenomena in Nanowire Biosensors

Kutovyi, Y. (Corresponding author)FZJ*

2021
Forschungszentrum Jülich GmbH Zentralbibliothek, Verlag Jülich
ISBN: 978-3-95806-544-4

Please use a persistent id in citations: http://hdl.handle.net/2128/28432  urn:nbn:de:0001-2021080939

Abstract: Single-trap phenomena (STP) in nanoscale transistor devices possess outstanding propertiesthat are promising for many useful and important applications including information technologiesand biosensing. In this thesis, a novel biosensing approach based on monitoring of STPparameters as a function of target biomolecules on the surface of liquid-gated (LG) silicon (Si)nanowire (NW) field-effect transistor (FET) biosensors was proposed and demonstrated. Toenhance STP dynamics and improve the efficiency of the approach, unique two-layer (TL) NWFETs with NW channels consisting of two Si layers with different concentrations of dopantswere designed and fabricated. A stable and leakage-free operation in liquid confirms the highquality of TL NW devices. At the same time, fabricated TL nanostructures are conceptuallydifferent from the conventional uniformly doped Si NWs and demonstrate more statisticallypronounced STP with considerably stronger capture time dependencies on drain current comparedto that predicted by classical Shockley-Read-Hall theory. A comprehensive analysis ofthe experimental data measured at low temperatures allowed the identification of the origin ofsingle traps in TL NWs as a vacancy-boron complex. Several important effects enabling the advancementof sensing capabilities of STP-based devices were revealed using fabricated TL NWFET biosensors. First, a significant effect of channel doping on the quantum tunneling dynamicsof charge carriers to/from a single trap was registered in TL nanostructures, analyzed, andexplained within the framework of proposed analytical model. Second, a distinct fine-tuningeffect of STP parameters by applying a back-gate potential to LG TL NW FETs was experimentallyrevealed and supported by numerical simulations. Such a unique feature of STP in TLNWs allows the sensitivity of STP-based biosensors to be enhanced in a well-controllable way.Furthermore, STP in NW FETs offer a great opportunity for the suppression of low-frequencynoise. Considering a trap occupancy probability (g-factor) as a signal, a new method for theestimation of g-factor noise was proposed and utilized. As a result, the effective suppressionof the low-frequency noise even beyond the thermal noise limit was experimentally and numericallydemonstrated. The derived analytical model showed an excellent agreement with theobtained results underlining the importance of STP for biosensing applications. Utilizing theunique advantages of STP in fabricated TL NW FET biosensors, several proof-of-concept applicationsincluding high-sensitive detection of target chemical and biological analytes: monoanddivalent ions, ascorbate molecules, and amyloid-beta peptides were demonstrated. Thus,the performed experiments together with the developed analytical models represent a major advancein the field of biosensors and pave the way for the next generation of novel ultrasensitivebioelectronic sensors exploiting single-trap phenomena.

Note: Dissertation, Dortmund, Univ, 2021

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Contributing Institute(s):

1. Bioelektronik (IBI-3)

Research Program(s):

1. 899 - ohne Topic (POF4-899) (POF4-899)

Appears in the scientific report 2021

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Database coverage:
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